1064nm波长双向泵浦的S波段掺铥石英光纤放大器

研究了1 064 nm波长双向泵浦的掺铥石英光纤放大器（TDSFA）,测量了信号开关增益随泵浦功率和信号波长的变化情况.在最大入纤功率1 400 mW泵浦下,放大器在1 485~1 517 nm的较宽范围内具有放大能力,最大增益3.76 dB.分析表明,弱的基态吸收和强的激发态吸收限制了放大器增益的进一步提高,表明上转换泵浦的TDSFA是可行的.     

New trend for optical signal-to-noise ratio of disturbed Raman fiber amplifier

In a distributed Raman fiber amplifier (DRFA), Raman amplification allows a lower signal launch powers to transverse the span above the noise floor while still increasing the optical signal-to-noise ratio (OSNR). It improves the noise figure and reduces the nonlinear penalty of fiber systems. In this paper, we demonstrate a new trend of OSNR at different pump configurations: forward, backward and bidirectional pumping for DRFAs as a function of fiber length. We also present the variation of OSNR with both input pump power and input signal power. It is found that forward pumping provides the highest OSNR, reaching its maximum value of 37 dB. However, backward pumping provides the smallest OSNR that has its maximum of 22 dB and the bidirectional pumping provides the moderate OSNR between the others having its peak of 26 dB.     

受扰陆上级联掺铒光纤放大器系统的特性分析

通过引入描述扰动程度的参数X和描述掺饵光纤放大器(EDFA)饱和特性陡度的参数T,本文推出了一个归一化的EDFA增益表达式,并据此对系统受扰后的信号恢复特性和误码率变化进行了分析。结果表明：对EDFA饱和程度较浅的陆上光纤通信系统,出现小于1dB(X≥0.8)的微扰时,光功率经一级EDFA即可恢复其原值的90%;系统经3dB扰动(X=0.5)后,光功率(信号和噪音功率之和)经过三级EDFA方能恢复到原值的90%,但系统误码率(BER)的恶化则在两个量级以上,且随着扰动开始点的后移而更加恶化。这说明为保证系统受扰后能正常工作,其光信噪比应有相当大的裕量。EDFA饱和越浅,系统受扰动的影响就越严重。     

掺铒光纤放大器中抽运问题的理论分析

依据掺铒光纤放大器的速率方程和光传输方程,在不计放大自发辐射的情况下,得出了抽运功率和信号增益在放大器中沿光纤分布的隐函形式的解析表达式,并利用数值模拟对三种抽运方式下的放大器特性进行了分析。     

Effect of steady-state conditions on self-pulsing characteristics of Yb-doped cw fiber lasers

Fiber laser resonator configurations have been analyzed theoretically on the basis of steady-state rate equations to optimize the laser conversion efficiency. Evolution of the pump- and signal powers and the saturated gain coefficient along the length of the laser medium has been simulated for high- and low-finesse resonators in forward- and backward pumping schemes. The corresponding fiber laser configurations have been setup to verify the results of simulation. Backward pumping configuration in an Yb-doped fiber laser has been found to be the most efficient, and in this configuration a maximum cw output power of 10.75 W in single transverse mode with an optical-to-optical conversion efficiency of 62.5% has been achieved. The laser output spectrum was peaked at 1093 nm with full-width at half-maximum (FWHM) line-width of about 9 nm. In the low-finesse resonator configuration, it has been found that experimental observations differ from theoretical simulation results. In this case, output power from both ends ceases to increase linearly beyond 1.8 W, and starts fluctuating due to the onset of strong random self-pulsing phenomenon. Our investigation shows that a non-uniform steady-state gain along the fiber length facilitates the self-pulsing process.     

A global design of an erbium-doped fiber and an erbium-doped fiber amplifier

A global design of an erbium-doped fiber and an open-loop erbium-doped fiber amplifier (EDFA) in a steady-state operation is discussed by applying genetic algorithms. Taking a signal gain and a bandwidth as objective functions, 7 parameters of the EDFA (erbium concentration, core radius, erbium-doped radius, refractive index difference, fiber length, pumping wavelength and signal power) are optimized by solving optical propagation equations, assuming a homogenous two-level active medium and a single-mode propagation. There is evidence to show that the 1480 nm pump utilized in usual EDFAs is not an optimal choice, which should be chosen around 1460 nm. The optimal core radius ranges 0.465–0.548 μm on pumping power 50–200 mW. Under different design objects and with different pumping powers, however, there are different optimal Er-doped concentrations, reflective index differences and fiber lengths. As a single fiber EDFA, 35 dB signal gain or 35 nm bandwidth is obtained with the 7 optimal parameters, 100 mW pumping power and 0.001 mW input signal power.     

Experimental Study on High Power and Efficiency Fiber Amplifier Module

l.IntroductionErbium-doPedfiberamp1ifier(EDFA)isattractiveinall-opticalcommunicationsys-temsduetoitSsuperiorityofhighgain,broadbandwidth,lownoiseandhighPOwer.Whenusedinhigh-sPeed,long-haulcommunicationanddistributionsystems,suchassolitoncommunication,WDM,FDM,AM-VSB,CATV,etc.,EDFAisdemandedofhighsignaloutputPowerbesidebroadbandwidth,lowdistortionandcrossta]k.ToobtainlargeoutputPowerwil1relatetomanyproblemslikethefibermaterial,pumpinglaser,fibcrcomPonent,manufacturetechnologyanddesig…     

LD泵浦掺铥(Tm3+)光纤激光器的数值分析

首先从掺铥光纤激光器的速率方程和光传输方程出发,建立数学模型,通过Matlab软件进行数值计算,分析了泵浦光和激光沿光纤的分布以及各能级离子数的变化.在不同掺杂浓度下,研究了小信号增益与入纤泵浦功率的关系以及泵浦光和激光功率与增益介质长度的关系.在不同泵浦功率下,研究了输出功率与输出耦合镜反射率的关系.进一步对不同泵浦吸收系数,研究了斜率效率和泵浦阈值与光纤长度的关系.分析结果表明存在最佳光纤长度和最佳耦合输出透过率,使得激光输出功率达到最佳值.     

分布式光纤拉曼放大器在长距离光传输系统中的优化设计

同时考虑接收光信噪比(OSNR)及非线性失真影响，对分布式光纤拉曼放大器在长距离光传输系统中的最优抽运方式进行了研究.利用变分法原理获得了在不记双瑞利背散射(DRB)影响时的最优信号功率分布函数——均匀分布，但考虑双瑞利散射影响时则不存在解析的最优分布函数.在分别考虑长、短光纤跨距的情况下，比较了三种具有代表性的分布式光纤拉曼放大方式，即双向二阶拉曼抽运、双向一阶拉曼抽运和拉曼+掺铒光纤放大器混合放大方式的性能.指出通过优化一阶抽运波长以及一阶到二阶抽运功率比，对称结构的双向二阶抽运在绝大部分情况下可以在 关键词： 光纤拉曼放大器 双瑞利背散射 变分法 光纤非线性     

Remotely Pumped Hybrid Amplifiers for Extended Bidirectional Passive Optical Networks

In this contribution, we optimize design parameters of hybrid optical amplifiers utilizing distributed Raman amplification in transmission fiber and gain of discrete, remotely pumped erbium-doped fiber amplifier (EDFA) for wideband, bidirectional operation in metropolitan area networks (MAN). The design is based on an application of a numerical model, which takes into account pump-to-pump and signal-to-signal interactions and generation of amplified spontaneous emission in the Raman amplifier and solves the standard rate-propagation equations in an erbium-doped fiber (EDF). We predict 12 dB gain across 72 nm of optical bandwidth with gain ripple better than 10%. The recently proposed serial topology of EDFA is considered; this enables the wideband, bidirectional operation of a hybrid amplifier with only two pump laser diodes emitting in the 1430 and 1480 nm bands.     

WDM系统中碲基掺铒光纤放大器泵浦问题的理论研究

依据均匀加宽四能级结构速率方程组和光功率传输方程组, 对WDM系统中碲基掺铒光纤放大器（EDTFA）的泵浦问题进行了理论研究,给出了三种泵浦方式小信号和大信号状态下EDTFA信号增益分布曲线和放大的自发辐射（ASE）噪声功率谱,在此基础上探讨了EDTFA泵浦方式与信号增益、ASE噪声的关系.     

光纤激光陀螺系统的优化设计

分析研究了光纤激光陀螺系统的工作原理和基本构成,根据系统中各器件的性能指标对光纤激光陀螺的基本结构、性能参数进行了计算机模拟优化设计。采用双向激射双向输出结构保证光路的互易性。利用光纤环形器、掺铒光纤和光纤Bragg光栅实现滤模、选模和压缩线宽功能。针对其输出信号特点,提出利用偏振分束的方式判断陀螺工作转动方向,并最终计算陀螺转动角速度的信号处理方案。     

S-band multiwavelength Brillouin Raman Fiber Laser

In this paper we propose and demonstrate an S-band Brillouin-Raman Fiber Laser (BRFL). The S-band BRFL utilizes a Dispersion Compensating Fiber (DCF) as the non-linear gain medium in a linear cavity configuration and amplified by two 1425 nm, 380 mW pumped Raman Fiber Amplifiers (RFAs). A Brillouin Pump (BP) signal of 1515 nm at 12 dBm in power is injected into the setup to generate Stokes lines via the Stimulated Brillouin Scattering (SBS) process. The S-band BRFL is able of generating a Brillouin comb with 32 Stokes lines with a flat peak output power of − 18 dBm. The best BP to Stokes power ratio of the system is determined to be 50:50, while a ratio of 70:30 is observed to generate Stokes with a higher peak power, but at the expense of the number of wavelengths. The S-band BRFL has many potential applications as multiwavelength sources for communications and sensors.     

Experimental and theoretical studies on a double-pass C-band bismuth-based erbium-doped fiber amplifier

Performance of a Bismuth-based Erbium-doped fiber amplifier is experimentally and theoretically investigated using 1480 nm pumping with double-pass scheme. In the theoretical analysis, the rate and power propagation equations are solved to examine the optimum length for the C-band operation as well as the gain and noise figure characteristics. The calculated small signal gain is 38 dB with gain variation of less than 3 dB. The measured gain is 4 dB lower due to spurious reflections which were ignored in the theoretical analysis. At input signal power of 0 dBm, a gain of 14.5 dB is obtained experimentally with gain variation of less than 1 dB within the wavelength region from 1530 to 1565 nm. The noise figure is less than 12 dB within this region.     

双向掺铒光纤放大器的特性分析

讨论了双向掺铒光纤放大器的结构方案,利用考虑放大的自发辐和北员耗影响的双向掺铒光纤放大器稳态放大速率方程模型分析的增益与掺铒光纤长度、输入信号光功率、帛运光功率及抽运方式等参数之间的关系,研究了单向和双向等功率抽运下正反向噪声系数随正反向信号光输入功率的变化行为。     

1480nm泵浦的掺饵光纤放大器上能级粒子数分布

本文建立了1480nm泵浦下掺饵光纤放大器的速率方程组,并利用这组方程对掺饵光纤放大器的上能级粒子数分布进行了数值分析,在同向泵浦、反向泵浦以及双向泵浦三种不同的泵浦方式下,会别给出了小信号(如,1μW)和大信号(如1mW)功率输入时掺饵光纤的上能级归一化粒子数分布曲线。     

Small signal gain and saturation intensity of a Yb:Silica fiber MOPA system

In this work, the small signal gain (γ₀) and signal saturation power (P_sat) of a continuous wave (CW) single-frequency ytterbium-doped (YD) double-clad (DC) fiber master oscillator power amplifier (MOPA) array has been determined in the optimum length. At first, we have obtained output versus input signal powers in the amplifier, using the coupled steady-state rate equations for the various end diode pumping such as co/counter propagation and bidirectional modes. On the other hand, the steady-state amplification relation was employed at a presumed γ₀ and P_sat as initial guess, to generate output signals. Then, using the least square method (LSM), those input/output signal powers were fitted by the best regression curve obtained from the amplification relation to determine the converged γ₀ and P_sat values. The analytical formulae for γ₀ and P_sat were derived using the rate equations as well.     

高功率光子晶体光纤放大器实验研究

利用掺Yb³⁺的光子晶体光纤作为光纤放大器的增益介质,采用反向抽运方式,分别从理论和实验方面研究了不同信号的增益特性,在信号光功率为6W,抽运光功率为160W时,获得了104W的输出功率.实验发现,当抽运功率大于一定值时,放大器输出会有一定的不稳定性,并影响输出功率的进一步提高. 关键词： 光子晶体光纤 光纤放大器 反向抽运 高功率     

High gain L-band erbium-doped fiber amplifier with two-stage double-pass configuration

An experiment on gain enhancement in the long wavelength band erbium-doped fiber amplifier (L-band EDFA) is demonstrated using dual forward pumping scheme in double-pass system. Compared to a single-stage single-pass scheme, the small signal gain for 1580 nm signal can be improved by 13.5 dB. However, a noise figure penalty of 2.9 dB was obtained due to the backward C-band ASE from second stage and the already amplified signal from the first pass that extracting energy from the forward C-band ASE. The maximum gain improvement of 13.7 dB was obtained at a signal wavelength of 1588 nm while signal and total pump powers were fixed at -30 dBm and 92 mW, respectively.     

国产光纤实现同带抽运3000W激光输出

同带抽运是目前实现高功率光纤激光器的有效手段.本文基于同带抽运方式,以国产25/250μm掺镱双包层光纤为增益光纤,构建了全光纤化的主控振荡器功率放大器.实验中采用的国产光纤是中国电子科技集团公司第四十六研究所采用化学气相沉积结合气相-液相复合掺杂工艺制备的,其Yb~(3+)离子的分布更均匀,吸收截面更大,吸收系数更高.实验中,在种子光功率为67.8 W、抽运总功率为3511 W的条件下,实现了3079 W的激光输出,斜效率为85.9%,光束质量M~2约为2.14,3dB带宽为1.4nm,这是目前基于国产光纤同带抽运方式实现的最高功率.理论和实验结果表明国产光纤制备技术不断成熟,已经具备承受高功率输出的能力.继续提高抽运功率,优化增益光纤长度,改良散热方式,国产光纤有望实现更高功率的激光输出.